This invention relates to processing chambers, and more particularly to mechanism for releasably latching and sealing the access door of a lyophilizer or other processing chamber housing which operates at sub-atmospheric or super atmospheric pressures.
Lyophilizers, commonly called freeze dryers, like many other industrial chambers require an access door that is capable of being releasably latched and sealed in closed condition in order for the chamber to be evacuated or pressurized.
Some conventionally employed latching mechanisms for such access doors require hardware that covers so much of the outside surface of the door that it is not possible to include in the door such desirable accessories as vision ports, sampling sub-chambers attached to such vision ports, which allow extraction of individual product vials without interrupting the production cycle, and sub-doors which are small doors within the main door for use in loading and unloading the interior shelves without requiring opening of the main door which promotes drastic intrusion.
An example of such conventional latching mechanisms is the arrangement of a plurality of radially extending spider arms movable outwardly into associated sockets by a central handwheel.
Other chamber access doors are secured releasably by a multiplicity of hinged latch bolts which are mounted on the chamber and are movable manually into notches in the periphery of the door and then rotated to press the door against a seal between the door and chamber. This type of latch mechanism requires considerable manual labor and time to open and close.
Still other chamber access doors are provided with a plurality of air cylinders which drive locking pins outwardly from the door into apertures in the chamber wall. An inflatable seal between the chamber wall and door serves to allow evacuation or pressurization of the chamber. Inadvertent deflation of the seal results in loss of vacuum or pressure in the chamber, with consequent destruction of the contents.